Prostate MRI: diffusion-weighted imaging at 1.5T correlates better with prostatectomy Gleason grades than TRUS-guided biopsies in peripheral zone tumours

Abstract

• Prostate cancer aggressiveness is probably underestimated and undersampled by routine ultrasound-guided biopsies. • Diffusion-weighted MR images show good linear correlation with prostate cancer aggressiveness. • DWI information may be used to improve risk-assessment in prostate cancer.

Prostate Cancer: The Role of Multiparametric Magnetic Resonance Imaging

“…15,32 The diffusion properties of a biological tissue are related to the amount of interstitial free water and permeability, reflecting tissue cellularity and the presence of intact cellular membranes. In general, cancer, abscesses, fibrosis, hemorrhage and cytotoxic edema may show restricted diffusion compared to than normal tissue, because of the high cellular density.…”

“…In prostate cancer (particularly in the peripheral zone, more frequently studied), normal glandular architecture is disrupted and replaced by aggregated cancer cells and fibrotic stroma, which constitutes an inhibitory environment to the movement of water. 16,32,33 The differences in water diffusion rates between normal and tumoral tissues can be depicted and quantitatively represented by apparent diffusion coefficient (ADC) maps, which are obtained with at least two b values. Restricted diffusion typically seen in prostate cancer leads to high signal on raw high b value DWI and low signal intensity on ADC maps (Fig.s 3b-c, 4c-d, 5c).…”

“…There is no absolute consensus about the optimal b value for prostate cancer detection, but it is known that higher b values may increase diffusion sensitivity by lowering the normal hyperintensity of tissues with long T2 relaxation times, such as the PZ. [32][33][34][35] Several studies showed significant differences in the mean ADC values between cancerous and normal tissues for the PZ and to a lesser extent for the TZ (36). However, other studies showed considerable overlap of ADC values between prostate cancer and benign conditions like BPH and A B D C prostatitis.…”

“…16,18,34,[37][38][39][40][41][42][43][44] There is also evidence of a significant negative correlation between the ADC values of prostate tumors and prostatectomy specimen Gleason scores. Bittencourt et al 32 suggested that ADC values perform better than TRUS guided biopsy Gleason scores in the correlation with prostatectomy Gleason scores. However, individual variability may decrease the diagnostic accuracy of ADC measurement for prostate cancer detection and localization.…”

Diffusion Weighted Imaging in Prostate Cancer a Review.

“…(22)(23)(24)26,27) Bittencourt et aland Yagci et al showed that the findings of DWI MRI correlate well with GS from prostatectomy specimen rather than biopsy specimen. (6,8) In general prostatectomy is performed in localized or locally advanced PC. PC positive DWI MRI findings (p=0.0059) and a high GS (8 or more) (p=0.0051),was associated with locally advanced PC which suggests that DWI MRI has positive result for PC with high malignancy.…”